The food industry uses a variety of additives (anti-oxidants, dyes, preservatives, sweeteners, emulsifiers, thickeners, stabilizers, flavourings, etc.) when preparing numerous food products.
Emulsifiers are used in the food industry when preparing a variety of products (sausage, pates, cheese for melting, fillings, etc.) with a view to creating an emulsion or for improving the colloidal stability, by reducing the aggregation or coalescence rate of the scattered particles. Natural emulsifiers are among the most common types of emulsifiers, for example lecithin, and those of synthetic origin, for example, monoglycerides, diglycerides and derivatives, for example, certain fatty acids, etc.
Stabilisers are added to the food products in order to prevent them from undergoing changes. The following are the most extensively used stabilisers in the food industry: gums, starches, dextrins, proteins, etc.
As is well known, the emulsifiers that are generally used in the food industry do not provide the stability required for emulsified meat products, so use is made of proteins that can be used for the purpose, which increases the cost of the final food product. In this sense, the proteins that are most extensively used are sodium caseinate and the soya protein in isolation. Sodium caseinate is obtained from skimmed milk, and 32 liters of skimmed milk are needed to obtain 1 kg of sodium caseinate, by means of a procedure that involves precipitating with hydrochloric acid, the lactic protein sensitive to acid. The precipitate of casein acid is neutralised with sodium hydroxide and is then dried by atomising, extrusion or by means of a roller system.
The soya protein in isolated form is obtained from soya flour whose fat has been removed by precipitation. Its emulsifying capacity is lower than caseinate, so greater proportions are generally used, usually 30% more, which has an effect on the end product. Furthermore, there is the disadvantage of it having a flavour that is undesirable (it tastes of soya).
Apart from sodium caseinate and the soya protein in isolated form, the use of emulsifiers from the citric ester family of monoglycerides and diglycerides from fatty acids has also been described for some hot emulsified products, these having a water/oil emulsifying effect. Because of their hydrophilic nature, the esters from monoglyceride citric acid can stabilise certain meat preparations, such as liver pâté. Pâtés are manufactured by mixing liver, fat and water at a temperature ranging from 40° C. to 45° C., at which the esters, in combination with the proteins in the liver, increase the stability during the interphases where the proteins act as supplementary hydrophilic stabilisers. However, the monoglyceride and diglyceride citric esters in fatty acids do not operate in cold temperatures.
Furthermore, a description has also been given of the use of sorbitane acids from fatty acids to improve the cold emulsifying potential of oil in water for sauces and mayonnaise with a low oil content.
In spite of the effort that has been made, it has not yet been possible to develop any formula based upon emulsifiers authorised by the food legislation for fatty acid family, regardless of whether they are glycerides or other esters, with emulsifying activity, which are capable of forming cold water/oil emulsions either with raw animal fat or other fats or oils used for food.